1. Field of the Invention
The present invention is in the field of control systems, and more specifically, is in the field of position based velocity estimation.
2. Discussion of the Prior Art
When a rover is moving quickly, the conventional approach is to take a fix as often as possible (like every 100 to 200 msec) and to calculate an instantaneous rover direction vector based on two rover positions: a current rover position, and a referenced future rover position as to where it should be at certain point in time. This approach works well when the rover is moving along at a relatively moderate speed so that the distance between fixes is greater than the error in the fix determination. For example, at 99 inches per second, or at 9 km/hour, if one takes a fix 10 times per second, the rover has moved about 10 inches between fixes. If a fix accuracy is 2 inches, then the position fix “noise” is about 20%. This is an acceptable level of noise because it can be filtered out.
On the other hand, if a rover is moving slowly (for example, at 1 km/hour, or at 11 inches per second), and if a fix is taken approximately 10 times per second, the rover will have moved about 1 inch between two fixes. If a fix accuracy is the same, that is about 2 inches, the position fix noise is 200%. This is an unacceptable level of noise.